Submission #2501768

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<int> a(2 * n), b(n), w(n);
    vector<char> c(2 * n);
    for (int i = 0; i < 2 * n; i++) {
        cin >> c[i] >> a[i];
        a[i]--;
        if (c[i] == 'B') b[a[i]] = i;
        else w[a[i]] = i;
    }

    ll ans = 0;
    for (int i = 0, j = 0, k = 0; k < 2 * n; k++) {
        int tar = -1;
        if (i == n) {
            tar = w[j];
            j++;
        } else if (j == n) {
            tar = b[i];
            i++;
        } else {
            if (abs(b[i] - k) < abs(w[j] - k)) {
                tar = b[i];
                i++;
            } else {
                tar = w[j];
                j++;
            }
        }

        for (int x = tar; x > k; x--) {
            if (c[x - 1] == 'B') b[a[x - 1]] = x;
            else w[a[x - 1]] = x;
            if (c[x] == 'B') b[a[x]] = x - 1;
            else w[a[x]] = x - 1; 
            swap(c[x - 1], c[x]);
            swap(a[x - 1], a[x]);    
            ans++;
        }
    }

    cout << ans << endl;
    return 0;
}

Submission Info

Judge Result